Witchwarper: Signature Spells

You've learned to cast some of your spells more flexibly. For each spell rank you have access to, choose one spell of that rank to be a signature spell. You don't need to learn heightened versions of signature spells separately; instead, you can heighten these spells freely. If you've learned a signature spell at a higher rank than its minimum, you can also cast all its lower-rank versions without learning those separately. If you swap out a signature spell, you can choose a replacement signature spell of the same spell rank at which you learned the previous spell. You can also retrain specifically to change a signature spell to a different spell of that rank without swapping any spells; this takes as much time as retraining a spell normally does.